1. Field of the Invention
This invention relates to a stencil printer, and more particularly to a stencil printer which can be linked with another printer which prints in a system other than the stencil printing.
2. Description of the Related Art
The stencil printer generally comprises a stencil making section which makes a stencil (imagewise perforates a stencil material) on the basis of bit map data obtained by reading an original by a built-in image reading means such as an image scanner or by expanding PDL (page description language) data sent from a computer or the like and an ink transfer section which transfers ink to printing papers through a stencil wound around a printing drum. Generally, the stencil printer is automatically set to the stencil making mode each time it receives a piece of PDL data or each time the built-in image reading means begins to read the image on an original, and the stencil making section starts to make a stencil. When the stencil making section finishes making a stencil, the working mode of the stencil printer is automatically switched to the ink transfer mode and the ink transfer section makes a desired number of copies by the use of the stencil made by the stencil making section. The working mode of the stencil printer is kept set to the ink transfer mode even a series of printing is finished until another piece of PDL data is sent thereto or another original is set. When only the number of copies to be additionally printed is set and the stencil printer is activated in this state, the stencil making section does not work and the ink transfer section makes desired number of additional copies by the use of the stencil which have been on the printing drum (additional printing).
There are employed in an office or the like various types of printers such as a laser beam printer, an ink jet printer, a dot printer and the like as well as a stencil printer.
These printers work in different printing systems. For example, the stencil printer makes a stencil and prints by transferring ink to printing papers through the stencil, whereas, in printers other than the stencil printer, no stencil is used. For example, in the case of a laser beam printer, a photosensitive drum is imagewise exposed to a laser beam, toner is caused to adhere to the exposed part of the photosensitive drum, and the toner on the photosensitive drum is transferred to a printing paper, and these steps are repeated for each copy.
Since these printers work in different printing systems, the time and/or cost required to output one copy greatly differs from each other depending on the type of the printer.
The following table 1 shows the time and cost required to output one copy in the case of a stencil printer (SP) versus the time and cost required to output one copy in the case of a laser beam printer (LBP) when the stencil printer and the LBP outputs output the same copies.
As can be understood from table 1, in the case of the stencil printer, the output time per one copy is shortened as the total number copies to be printed increases and the cost per one copy is reduced as the total number copies to be printed increases since it is necessary to make a stencil and to wind the stencil around the printing drum irrespective of the number of copies to be printed. On the other hand, in the case of the laser beam printer, the output time per one copy and the cost per one copy are both constant irrespective of the number of copies to be printed. Accordingly, the stencil printer is advantageous over the laser beam printer (or other printers) when the total number of copies to be printed (of the same contents) is large whereas the laser beam printer (or other printers) is advantageous over the stencil printer when the total number of copies to be printed (of the same contents) is small.
There has been proposed, as disclosed in Japanese Unexamined Patent Publication No. 1(1989)-217384, a system in which a stencil printer and one or more non-stencil printer (a printer which works in a printing system different from the stencil printer) are linked and the stencil printer is used when the number of copies to be printed is large, whereas the non-stencil printer is used when the number of copies to be printed is small.
However, this system involves a problem that when a small number of additional copies are to be printed and the system is activated with only the number of additional copies set, the non-stencil printer is selected and additional copies are printed by the non-stencil printer, although a large number of the same copies have been printed by the stencil printer and the stencil is still wound around the printing drum, that is, although use of the stencil printer is advantageous over use of the non-stencil printer from the viewpoint of both the cost and the quality of the printings. That is, there is a demand that additional copies should be printed by the stencil printer irrespective of the number thereof in the case where the stencil is still on the printing drum.
In view of the foregoing observations and description, the primary object of the present invention is to provide a stencil printer which can be linked with a non-stencil printer so that print is made by the stencil printer when the number of copies to be printed is not smaller than a predetermined value and print is made by the non-stencil printer when the number of copies to be printed is smaller than the predetermined value and at the same time print is made by the stencil printer irrespective of the number of copies when copies of the same contents as those printed by the use of the stencil on the printing drum of the stencil printer are to be additionally printed.
The object can be accomplished by a stencil printer which can be linked with a non-stencil printer comprising
a copy number setting means for setting a number of copies to be printed,
a working mode setting means for setting the working mode of the stencil printer to a stencil making mode or an ink transfer mode,
a stencil printing means consisting of a stencil making section which makes a stencil when the working mode of the stencil printer is set to the stencil making mode by the working mode setting means and an ink transfer section which transfers ink to a printing paper through the stencil made by the stencil making section when the working mode of the stencil printer is set to the ink transfer mode by the working mode setting means, and
a printer switching means which causes the stencil printing means to print when the number of copies set by the copy number setting means is not smaller than a predetermined threshold value and causes the non-stencil printer to print when the number of copies set by the copy number setting means is smaller than the predetermined threshold value, wherein the improvement comprises
a switching inhibiting means which inhibits the printer switching means from switching between the stencil printing means and the non-stencil printer when the working mode of the stencil printer is the ink transfer mode.
The xe2x80x9cworking mode setting meansxe2x80x9d automatically sets the working mode of the stencil printer to a stencil making mode each time it receives a piece of PDL data or each time the built-in image reading means begins to read the image on an original and to the ink transfer mode when the stencil making section finishes making a stencil. It is preferred that the working mode setting means can be manually operated to set the working mode of the stencil printer to the stencil making mode or to the ink transfer mode.
The stencil printer in accordance with the present invention may be contained in a housing separate from that of the non-stencil printer and connected with the non-stencil printer through an external interface such as a LAN cable or a parallel cable, or may be contained in a housing together with the non-stencil printer and connected with the non-stencil printer through an internal interface.
In accordance with the stencil printer of this invention, the stencil printer and the non-stencil printer can be selectively used according to the number of copies to be printed. At the same time, the stencil printer can be used irrespective of the number of copies to be additionally printed so long as the stencil for the copies is still wound around the printing drum, whereby additional copies can be printed at lower cost.